Why the panel text changed?

Hello, I ran into a strange problem:

I have two panels in sequence, both of them displayed from the same JFrame. The JFrame has an Image in the "West" (BorderLayoutManeger). The image is shared between the two panels. The problematic part is the JPanel in the center, which is different from panel to panel.

The first time, a new JPanel is added and a non-editable JEditorPane is added to the JPanel. It displays Text "AAA". I can minimize or hide the panel and then bring the panel back. No problem.

Later a new JPanel is created and a JLabel is added the the new JPanel, and the the new JPanel is set to the center of the JFrame. It first displays text "BBB" properly. But when I minimize or hide the panel, and then bring the panel back, the panel goes back to text "AAA". And it always displays "AAA".